Friction tubes

ABSTRACT

A torsion shaft assembly includes a torque carrying shaft including a driven end configured for receiving torque input to the torque carrying shaft and a driving end configured for outputting torque output from the toque carrying shaft. The torque carrying shaft includes an axial facing damping interface surface axially between the driven end and the driving end. A friction tube is disposed outboard of the torque carrying shaft. The friction tube is connected at a first axial location to be driven by the torque carrying shaft. The friction tube includes an axial facing damping interface surface that abuts the axial facing damping interface surface of the torque carrying shaft, forming a damping interface to provide frictional dampening against angular vibrations occurring as differential angular displacement between the driven end and the driving end of the torque carrying shaft.

BACKGROUND 1. Field

The present disclosure relates to torque bearing shafts, and moreparticularly to dampening for torque bearing shafts.

2. Description of Related Art

Torsion shafts can undergo vibration which can limit the useable life ofthe torsion shafts. Among the vibrations are those that act in theangular or circumferential direction. Traditionally, a torsion shaftmust be designed to have enough mass to handle the angular vibrationsfor the entire useable life of the torsion shaft.

The conventional techniques have been considered satisfactory for theirintended purpose. However, there is an ever present need for improvedsystems and methods for handling vibrations in torsion shafts. Thisdisclosure provides a solution for this need.

SUMMARY

A torsion shaft assembly includes a torque carrying shaft including adriven end configured for receiving torque input to the torque carryingshaft and a driving end configured for outputting torque output from thetoque carrying shaft. The torque carrying shaft includes an axial facingdamping interface surface axially between the driven end and the drivingend. A friction tube is disposed outboard of the torque carrying shaft.The friction tube is connected at a first axial location to be driven bythe torque carrying shaft. The friction tube includes an axial facingdamping interface surface that abuts the axial facing damping interfacesurface of the torque carrying shaft, forming a damping interface toprovide frictional dampening against angular vibrations occurring asdifferential angular displacement between the driven end and the drivingend of the torque carrying shaft.

A helical spring can be engaged with the friction tube on a driven endof the friction tube to bias the friction tube toward the dampinginterface. The friction tube can be engaged with drive flats of thetoque carrying shaft. The drive flats of the torque carrying shaft canbe more proximate the driven end of the torque carrying shaft than tothe driving end. The torque carrying shaft and the friction tube can beat least ten times longer than a distance from the driven end of thetorque carrying shaft to the drive flats taken in an axial direction.The drive flats of the torque carrying shaft can be defined as facets ina radially extending flange of the torque carrying shaft.

The axial facing damping interface surface of the torque carrying shaftcan be defined on a radially extending flange of the torque carryingshaft. The radially extending flange can be more proximate the drivingend than the driven end. The torque carrying shaft and the friction tubecan be at least ten times longer than a distance from the driving end ofthe torque carrying shaft to the radially extending flange taken in anaxial direction.

The torque carrying shaft can be hollow defining a fluid passagetherethrough. The torque carrying shaft can include one or more boresdefined radially therethrough from the fluid passage to an annular spacebetween the torque carrying shaft and the friction tube for passage offluids between the fluid passage and the annular space. The frictiontube can include one or more bores defined radially therethrough fromthe annular space to an exterior of the friction tube for passage offluids between the annular space and the exterior.

These and other features of the systems and methods of the subjectdisclosure will become more readily apparent to those skilled in the artfrom the following detailed description of the preferred embodimentstaken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

So that those skilled in the art to which the subject disclosureappertains will readily understand how to make and use the devices andmethods of the subject disclosure without undue experimentation,preferred embodiments thereof will be described in detail herein belowwith reference to certain figures, wherein:

FIG. 1 is a cross-sectional side-elevation view of an embodiment of atorsion shaft assembly constructed in accordance with the presentdisclosure, showing the torque carrying shaft and the friction tube;

FIG. 2 is a cross-sectional side-elevation view of a portion of thetorsion shaft assembly of FIG. 1, showing the drive flats; and

FIG. 3 is a cross-sectional side-elevation view of a portion of thetorsion shaft assembly of FIG. 1, showing the friction interface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings wherein like referencenumerals identify similar structural features or aspects of the subjectdisclosure. For purposes of explanation and illustration, and notlimitation, a partial view of an embodiment of a torsion shaft assemblyin accordance with the disclosure is shown in FIG. 1 and is designatedgenerally by reference character 100. Other embodiments of systems inaccordance with the disclosure, or aspects thereof, are provided inFIGS. 2-3, as will be described. The systems and methods describedherein can be used to dampen angular vibration in torque shafts.

A torsion shaft assembly 100 includes a torque carrying shaft 102including a driving end 106 configured for receiving torque input to thetorque carrying shaft 102 and a driven end 104 configured for outputtingtorque output from the toque carrying shaft 102. The torque carryingshaft 102 includes an axial facing damping interface surface 108(labeled in FIG. 3) axially between the driven end 104 and the drivingend 106. A friction tube 110 is disposed outboard of the torque carryingshaft 102. The friction tube 110 is connected at a first axial location112 to be driven by the torque carrying shaft 102. The friction tube 110includes an axial facing damping interface surface 114 that abuts theaxial facing damping interface surface 108 of the torque carrying shaft102, forming a damping interface 116 to provide frictional dampeningagainst angular vibrations occurring as differential angulardisplacement about rotational axis A between the driven end 104 and thedriving end 106 of the torque carrying shaft 102.

A helical spring 118 can be engaged with the friction tube 110 on thedriven end 104 of the friction tube 110 to bias the friction tube 110toward the damping interface 116 of FIG. 3, i.e. pushing the frictiontube 110 to the right along the rotational axis A as oriented in FIG. 2.As shown in FIG. 2, the friction tube 110 is engaged with drive flats120 of the toque carrying shaft 102. The drive flats 120 of the torquecarrying shaft 102 are more proximate the driven end 104 of the torquecarrying shaft 102 than to the driving end 106. As shown in FIG. 1, thetorque carrying shaft 102 and the friction tube 110 are at least tentimes longer (in the axial direction of the rotational axis A) than adistance D1 from the driven end 104 of the torque carrying shaft 102 tothe drive flats 120. The drive flats 120 of the torque carrying shaft102 are defined as facets in a radially extending flange 122 of thetorque carrying shaft 102.

With reference now to FIG. 3, the axial facing damping interface surface108 of the torque carrying shaft 102 is defined on a radially extendingflange 124 of the torque carrying shaft 102. The radially extendingflange 124 is more proximate the driving end 106 than the driven end 104(each end 106, 104 is shown in FIG. 1). As shown in FIG. 1, the torquecarrying shaft 102 and the friction tube 110 are at least ten timeslonger than a distance D2 from the driving end 106 of the torquecarrying shaft 102 to the radially extending flange 124 taken in theaxial direction.

With reference again to FIG. 1, the torque carrying shaft 102 is hollowdefining a fluid passage 126 therethrough. The torque carrying shaft 102includes one or more bores 128 defined radially therethrough from thefluid passage 126 to an annular space 130 between the torque carryingshaft 102 and the friction tube 110 for passage of fluids between thefluid passage 126 and the annular space 130. The friction tube 110includes one or more bores 132 defined radially therethrough from theannular space 130 to an exterior 134 of the friction tube 110 forpassage of fluids between the annular space 130 and the exterior 134.

Systems and methods as disclosed herein can allow for dampening angularvibrations in torsion shafts. Torsion shafts with vibration dampening asdisclosed herein can be reduced in mass and still manage the same loadsand useful life time as more massive traditional torsion shafts withoutsuch dampening.

The methods and systems of the present disclosure, as described aboveand shown in the drawings, provide for angular vibration damping intorque carrying shafts. While the apparatus and methods of the subjectdisclosure have been shown and described with reference to preferredembodiments, those skilled in the art will readily appreciate thatchanges and/or modifications may be made thereto without departing fromthe scope of the subject disclosure.

What is claimed is:
 1. A torsion shaft assembly comprising: a torquecarrying shaft including a driven end configured for receiving torqueinput to the torque carrying shaft and a driving end configured foroutputting torque output from the toque carrying shaft, wherein thetorque carrying shaft includes an axial facing damping interface surfaceaxially between the driven end and the driving end, wherein the torquecarrying shaft is hollow defining a fluid passage therethrough; and afriction tube disposed outboard of the torque carrying shaft, whereinthe friction tube is connected at a first axial location to be driven bythe torque carrying shaft, and wherein the friction tube includes anaxial facing damping interface surface that abuts the axial facingdamping interface surface of the torque carrying shaft, forming adamping interface to provide frictional dampening against angularvibrations occurring as differential angular displacement between thedriven end and the driving end of the torque carrying shaft.
 2. Thetorsion shaft assembly as recited in claim 1, further comprising ahelical spring engaged with the friction tube to bias the friction tubetoward the damping interface.
 3. The torsion shaft assembly as recitedin claim 1, wherein the friction tube is engaged with drive flats of thetoque carrying shaft.
 4. The torsion shaft assembly as recited in claim3, wherein the drive flats of the torque carrying shaft are moreproximate the driven end of the torque carrying shaft than to thedriving end.
 5. The torsion shaft assembly as recited in claim 3,wherein the drive flats of the torque carrying shaft are defined asfacets in a radially extending flange of the torque carrying shaft. 6.The torsion shaft assembly as recited in claim 3, wherein the torquecarrying shaft and the friction tube are at least ten times longer thana distance from the driven end of the torque carrying shaft to the driveflats taken in an axial direction.
 7. The torsion shaft assembly asrecited in claim 1, wherein the axial facing damping interface surfaceof the torque carrying shaft is defined on a radially extending flangeof the torque carrying shaft.
 8. The torsion shaft assembly as recitedin claim 7, wherein the radially extending flange is more proximate thedriven end than the driving end.
 9. The torsion shaft assembly asrecited in claim 8, wherein the torque carrying shaft and the frictiontube are at least ten times longer than a distance from the driving endof the torque carrying shaft to the radially extending flange taken inan axial direction.
 10. The torsion shaft assembly as recited in claim1, wherein the torque carrying shaft includes one or more bores definedradially therethrough from the fluid passage to an annular space betweenthe torque carrying shaft and the friction tube for passage of fluidsbetween the fluid passage and the annular space.
 11. The torsion shaftassembly as recited in claim 10, wherein the friction tube includes oneor more bores defined radially therethrough from the annular space to anexterior of the friction tube for passage of fluids between the annularspace and the exterior.
 12. The torsion shaft assembly as recited inclaim 1, wherein the friction tube is engaged with drive flats of thetoque carrying shaft, wherein the drive flats of the torque carryingshaft are defined as facets in a first radially extending flange of thetorque carrying shaft, wherein the axial facing damping interfacesurface of the torque carrying shaft is defined on a second radiallyextending flange of the torque carrying shaft.
 13. The torsion shaftassembly as recited in claim 12, further comprising a helical springengaged with the friction tube on a driven end of the friction tube tobias the friction tube toward the damping interface.
 14. The torsionshaft assembly as recited in claim 12, wherein the torque carrying shaftand the friction tube are at least ten times longer than a distance fromthe driven end of the torque carrying shaft to the drive flats taken inan axial direction and are at least ten times longer than a distancefrom the driving end of the torque carrying shaft to the radiallyextending flange taken in an axial direction.